Because winning isn't as cool if you don't lose first.
1. Failure motivates.
Yeah that's a completely awful thing to say, but it's true. Whenever you suck at something it makes you want to reach higher, aim farther and all that other cliche bullshit they paste on classroom walls. The biggest effect failure has had on my life, is that it made me want things more. Improvement is the only thing that happens after you fail if you keep your head up.
All you have to do to take things in stride is realize that failure happens to everyone and there isn't anything wrong.
2. Failing makes you more fearless.
If you've already fallen off the cliff then why should you fear getting pushed?
Honestly, failing at something just makes you more badass. Where everyone else you know is safe on the shore of "doing okay" island, you're down in the jagged rocks of "oh shit" canyon. Get it? Hitting bottom is not a weekend retreat, but it's better than never knowing.
3. You'll learn to work harder.
You've got to be horrible at something before you get good right? Nobody just becomes a "great" out of thin air. Hard work and dedication, no matter how played out, always pay off. If you're actually doing your job and not pretending, you'll get ahead. Failure is just an indicator that you're not doing your best, and that's okay. Because you're human right?
Good. So learn to work harder and smarter and you'll get over the failure and meet success.
4. You'll get a bit of perspective.
Have you ever met someone who acts like they've never failed?
They're effing annoying. The worst part about that kind of person is they think they're invincible. It'll be a rude awakening when they finally screw up, and you...having failed before will laugh. Because you know there's a light at the end of the tunnel.
People who say they haven't failed are lying. It's also dumb to not acknowledge failure because you will gain perspective. It's an amazing feeling to know that you can do better.
5. Failure isn't the end of the world. In fact, it's the beginning.
Remember when you were learning how to ride a bike and you fell off a million time? Yeah...it sucks and you feel like you've failed, but it's not the end of the world. You may get some scrapes and scratches but it didn't kill you.
Fear of failure comes from our lack of self-assurance. We believe that if we make one false move, we're done. That's just not the case. You probably fell off your bike a million times before riding it with ease. And just because you're learning something at a higher level, with more pressure attached does not mean the same principle isn't true.
Just get up and keep moving.